If the mean of 5 observations x, x + 2, x + 4, x + 6 and x + 8 is 11, find the value of x.
Mean of the observation is given by –
So, adding the given observations, we get
Sum of the given observations = x + (x + 2) + (x + 4) + (x + 6) + (x + 8)
= x + x + 2 + x + 4 + x + 6 + x + 8
= 5x + 20
Total number of observations = 5
Mean = 11 (Given)
⇒
⇒ 55 = 5x + 20
⇒ 5x = 55 – 20 = 35
⇒ x = 7
Thus, x = 7